Commercial airlines typically have significant numbers of aircraft and serve dozens, if not more, of geographically diverse markets. Day-to-day operations require coordination of a variety of different business functions, including crew scheduling, maintenance, schedule planning, dispatch, equipment scheduling, purchasing, and the like. Because many of the different business functions are interdependent, changes to one aspect of the operations can have an effect on other parts of the overall business. The logistics behind coordinating operations is further complicated by the geographic distribution of markets.
Generally, most of the operations of a commercial airline are centered around flight schedules. As with the coordination of day-to-day operations, the design of the overall flight schedule for a commercial airline involves complex interactions of numerous factors. Schedule design must take into account consumer demand, the ability to make connecting flights, maintenance requirements, gate availability, flight times and distances, airport restrictions and curfews, the number of available aircraft, and the like. Because of these various factors and the need to coordinate other business functions with the overall flight schedule, changes to a schedule design are generally performed weeks or even months in advance of implementing a change. The need for such advance planning limits the flexibility of commercial airlines in adapting to an evolving business environment, increasing efficiency, or otherwise modifying the overall flight schedule.
One important factor in designing a flight schedule is the manner in which flights are spaced between and within markets to appropriately meet consumer demand. The distribution of flights in an appropriate manner is typically a complex task. For example, designing a flight schedule for a particular market involves the consideration of both demand for a particular departure time at the market as well as the distribution of demand among flights at and around that particular departure time. Numerous other factors can also impact the process of designing flight schedules, including limited availability of aircraft and other physical resources, maintenance requirements, legal and regulatory requirements, and personnel availability.